Field of the Invention
The present invention relates to a power supply control technique using a sensor which detects an object.
Description of the Related Art
There is known a technique that an image forming apparatus recovers from a power saving state when a sensor provided in the image forming apparatus detects a person approaching the image forming apparatus (Japanese Patent Laid-Open No. 2012-203132). There is also known a technique of, when detecting the approaching person by using the sensor, operating in a different way between a case in which detection is performed at a position away from the image forming apparatus and a case in which detection is performed at a position close to the image forming apparatus.
More specifically, an operation of flashing a predetermined button or the display of an authentication device when the person at the position away from the image forming apparatus has been detected and an operation of recovering the image forming apparatus from a sleep state when the person at the position close to the image forming apparatus has been detected are performed.
At this time, the purpose of flashing the predetermined button or the display of the authentication device is to let the person know that he or she has been detected by the sensor and to lead a user of the image forming apparatus to a next operation (Japanese Patent Laid-Open No. 2011-112309). That is, in this case, the user of the image forming apparatus is prompted, by flashing the predetermined button or the display of the authentication device, to press the flashing button or perform personal authentication by the authentication device.
The sensor used in the above-described image forming apparatus is generally configured to receive a signal generated by detecting the person and determine that the person has been detected if the received signal exceeds a predetermined threshold. At this time, in order to detect the person at the position away from the image forming apparatus, it is better to detect the person even in a small input amount by lowering the threshold. On the other hand, in the case in which the person is detected at the position close to the image forming apparatus, it is better to raise the threshold so as not to recover the image forming apparatus from the sleep state upon reacting to the person passing in front of it and to recover the image forming apparatus from the sleep state when the sensor detects the person for a predetermined time. When performing the different operation for each region as described above, the necessity to control the threshold (sensitivity) of the sensor arises.